Online measurements in refineries

A refinery is a factory or installation where a raw material or product is purified (often petroleum) or separated and processed into pure components / fractions. Examples of products are gasoline, gas, naphtha, propane, butane, fuel oil, lubricants, heavy fuel oil and sulfur.

When the petroleum arrives at the refinery, it is a mixture of substances. In order to make optimum use of the installations present in a refinery, oil with specific properties is required. In complex refineries, a mixture (so-called 'crude mix') is made for this purpose from oils that may come from oil fields all over the world. The more extensive the installations in a refinery, the more flexible it is possible to respond to a specific demand. In addition, people are less dependent on foreign oils.

The density of the type of petroleum determines whether it is a light, medium or heavy type of petroleum or crude. The viscosity, paraffin and sulfur content are also important for the way in which the production process should be set up precisely.

There are also other types of 'oil refineries', such as those for vegetable and animal oils, which are refined to make them suitable for consumption or to extract usable raw materials. The chemical and physical processes used are quite different from those used in the refining of petroleum. Below we only discuss the processing of petroleum and the (inline) instruments that are important in this regard.

Processing petroleum

The processing of petroleum can roughly be reduced to 4 steps:

1. Separation

2. Purification

3. Improvement

4. Mixing

The refining process

Separation

Petroleum is made up of thousands of different hydrocarbons. Each of these compounds has a unique boiling point. Distillation of the crude oil is started in a refinery.

Here, a number of fractions (constituents) are separated on the basis of the boiling point;

• Gas (C4)

• Naphtha (C8)

• Petrol (C8)

• Kerosene (C12)

• Gas oil / fuel oil (C16)

• Residue (C16 +)

Refining therefore produces different petroleum fractions with increasing molecular weight; they are distinguished by a difference in boiling point from low (gaseous and liquid) such as LPG and petrol, to high such as fuel oil, residues, bitumen and coke (liquid and solid). The evaporated (gaseous) fractions are collected in a large distillation tower. The liquid and solid fractions are also separated on the basis of their molecular weight. The residue has a lower economic value, therefore some of it is cracked. It may also be that the demand for another product is higher. For example, if kerosene cannot be distilled directly from petroleum, it can be obtained by cracking it.

Purification

When the products are separated, they are purified. This process also takes place through heating.

Improvement

Some refined products undergo a further improvement step to be made suitable for a particular application, such as gasoline.

Mixing

All different products are then kept in large storage tanks. A number of products are still being mixed and are suitable for use after this phase.

Storage and sustainability

Storage takes place on-site at the refinery itself or at suppliers of independent storage of bulk goods. Making refineries more sustainable is not only about energy use and CO2 emissions, but SO2 emissions, waste and water pollution are also relevant. Extensive desulfurization is important for environmental purposes, but also to obtain a lot of hydrogen, so that refining can take place without the use of heavy fuel oil production.

In-line analysis of gas flows in refineries

Refinery gas streams are complex mixtures of gases produced in the refining processes. Determining the composition is not difficult, but it is essential. Product quality and efficiency of the refining process depend on the ability to perform this analysis.

The Teledyne Falcon High Speed Compact Gas Chromatograph is ideally suited for refinery gas analysis, i.e. solid gases and C1-C6 and hydrocarbons for inline and portable process control and laboratories in minutes.

Characteristics:

Enables greater product throughput for higher revenues and profits.
Smaller dimensions provide more work space (space is often scarce)
Speed and precision for a faster turnaround time (50 times faster than traditional GCs)
Lowering utility costsFastest analysis time in the industry for refinery gas, with excellent performance and reliability
The patented resistively heated stainless steel capillary column module and its thermal management system provide a paradigm shift in GC analysis.

Read more about accurate measurements with the hydrocarbon analyzer here (more GC instruments).

Photo: Teledyne Falcon GC

Inline measurement of the viscosity of oil products

A quick and correct measurement of all types of oil products (fuels, crude oil, heating oil) affects storage, handling, operating conditions and/or makes quality control more efficient, depending on the type of instrument. The Sofraser Thermoset allows online measurements at 2 reference temperatures and the calculation of the viscosity index according to ASTM D 2270-04. Also read the article here: How do you choose a process viscometer when the test standard (ASTM D445) is a lab measurement?

High Viscosity Fuels or fuels with a high viscosity are products that generate combustion from residues. These cannot be used for combustion without a viscometer. Sometimes density meters are also used, but they are of insufficient value when it comes to combustion efficiency.

Photo: Sofraser Thermoset

More information about inline measurements in refining processes?

For more information, advice or a test, please contact our product managers